The production of glass fibers is well known. In general, molten glass is introduced into a bushing having an apertured, or orificed, bottom plate. Molten glass is caused to flow as individual filaments through the apertures of the plate. The filaments are sized, gathered into a strand and the strand is wound as a package on a collet of a winder.
In order to increase the production rate from such bushings, various methods have been employed. One method involves impinging a cooling gas, such as air, on the orificed plate to eliminate stagnant gas pockets from the outer face of the bushing plate and to cool the molten glass cones formed at the orifices. This impingement aids in maintaining fiber separation and allows a significant increase in the number of orifices which can be positioned in the plate.
As this process has developed, a major problem has arisen in that gas cooling becomes less effective as the size of the orifice plates increases for the purpose of increasing production. As the number of filaments drawn from an orifice plate increases, the extent to which the cooling gas is enabled to effectively penetrate the mass of filaments decreases. This dictates that orifice plates with large numbers of apertures must be very long in relation to their width. This creates problems with fitting such bushings to existing forehearths, heating such bushings and maintaining a uniform heat pattern, feeding glass from the forehearth without channelling, and the like.
The method and apparatus of this invention is directed towards the solution of those problems and relates to bushings, having tips or tipless, from which fibers are drawn as an array of fibers; that is, the fibers are drawn from an annular area in which are positioned a plurality of orifices substantially completely surrounding an area positioned centrally of the plate in which no orifices are positioned.